[FFmpeg-user] Specifying input and output formats with pipes

[belcampo]

On 07/19/11 18:08, Rhodri James wrote:
> On Tue, 19 Jul 2011 16:42:44 +0100, belcampo <belcampo at zonnet.nl> wrote:
>
>> On 07/19/11 17:00, Rhodri James wrote:
>>> Hi folks,
>>>
>>> I have a mildly convoluted transcoding requirement that I'm having
>>> difficulty translating into command-line parameters to ffmpeg.
>>>
>>> I'm using ffmpeg as part of a Unix pipe chain, so the input is coming on
>>> stdin and the output must go via stdout. My input stream is MPEG-4/2
>>> wrapped in an H.222 transport stream. For a first step I wanted
>>> MPEG-4/10 output, so I hauled out libx264:
>
> OK, so I completely confused myself describing this: what I have is
> PES-wrapped MPEG-4/2, and what I initially wanted was MPEG-4/10 in a
> transport stream. That should make my command line make a whole lot
> more sense.
>
>>>
>>>> ffmpeg -i pipe: -f mpegts -vcodec libx264 pipe: 2>ffmpeg.log
>>>
>>> That appeared to work, as far as I can tell, though ffmpeg was very
>>> sniffy about the headers. My test clip is too short to show anything
>>> much (thanks everso, dear customer), but something is getting through
>>> the experience. So far, so tentatively good.
>>>
>>> Now, for obscure and hopefully temporary reasons, I need to wrap that
>>> H.264 output in MP4. How on earth do I do that? All I can glean from the
>>> docs is that I should give my output file a ".mp4" suffix and all will
>>> be well, but of course my "output file" is a pipe. There doesn't seem to
>>> be any option to tell ffmpeg I want both H.264 transcode and MP4
>>> wrapping.
>
>> The docs should also have told that -f mp4 makes this work, the
>> extension-thing is 'guessing'. With mp4 it's not that difficult but a
>> .mpg extension could mean ps or ts, for program or transport-stream.
>
> The docs keep leaving me thinking "-f" is forcing _input_ format,
> but that's a separate matter. Unfortunately replacing "-f mpegts" with
> "-f mp4" fails for me. Here's the (trimmed) log:
>
>
> ffmpeg version 0.7-rc1, Copyright (c) 2000-2011 the FFmpeg developers
> built on Jul 6 2011 19:37:39 with gcc 4.5.2
> configuration: --enable-gpl --enable-libx264
> libavutil 50. 40. 1 / 50. 40. 1
> libavcodec 52.120. 0 / 52.120. 0
> libavformat 52.108. 0 / 52.108. 0
> libavdevice 52. 4. 0 / 52. 4. 0
> libavfilter 1. 77. 0 / 1. 77. 0
> libswscale 0. 13. 0 / 0. 13. 0
> [*snip whinging about incomplete headers*]
> Input #0, mpeg, from 'pipe:':
> Duration: N/A, bitrate: N/A
> Stream #0.0[0x1e0]: Video: mpeg4, yuv420p, 320x240 [PAR 1:1 DAR 4:3],
> 30k tbr, 90k tbn, 30k tbc
> [buffer @ 0x211f0e0] w:320 h:240 pixfmt:yuv420p
> [libx264 @ 0x211ec20] Default settings detected, using medium profile
> [libx264 @ 0x211ec20] using SAR=1/1
> [libx264 @ 0x211ec20] MB rate (9000000) > level limit (983040)
> [libx264 @ 0x211ec20] using cpu capabilities: MMX2 SSE2Fast SSSE3
> FastShuffle SSE4.2
> [libx264 @ 0x211ec20] profile High, level 5.1
> [libx264 @ 0x211ec20] 264 - core 106 Ubuntu_2:0.106.1741-3 -
> H.264/MPEG-4 AVC codec - Copyleft 2003-2010 -
> http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0
> analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1
> me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11
> fast_pskip=1 chroma_qp_offset=-2 threads=1 sliced_threads=0 nr=0
> decimate=1 interlaced=0 constrained_intra=0 bframes=3 b_pyramid=2
> b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250
> keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr
> mbtree=1 bitrate=200 ratetol=1.0 qcomp=0.60 qpmin=10 qpmax=51 qpstep=4
> ip_ratio=1.40 aq=1:1.00
> [mp4 @ 0x211dbe0] muxer does not support non seekable output
> Output #0, mp4, to 'pipe:':
> Metadata:
> encoder : Lavf52.108.0
> Stream #0.0: Video: libx264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], q=2-31,
> 200 kb/s, 90k tbn, 30k tbc
> Stream mapping:
> Stream #0.0 -> #0.0
> Could not write header for output file #0 (incorrect codec parameters ?)
>
Please don't trim your actual command-line, I have to guess what you did.
ffmpeg -i source.whatever -vcodec whatyouwant wuthwhatever options -f 
mpegts resultingformat
This is the simplified standard form of a command-line.